Mowers and cutters for cutting vegetation are of various types. Non-crop vegetation such as grass and weeds is most often cut with a rotary mower, where a cutting blade element rotates under a deck to cut and chop the vegetation. The cutting blade element can be a large blade rotating about its midpoint, or can be a disc with blades pivotally mounted thereon so as to reduce damage when striking an obstacle. Numerous variations of cutting blade elements are known.
Rotary mowers often include two, three, or more mower decks mounted side by side. The decks are offset fore and aft to provide the required overlap from the rotating blade under one deck to that of the adjacent deck, and the outside decks, or wings, fold upward to allow for transport. Such wider rotary mowers are most often of the trailing type, wherein the mower is supported by wheels behind the decks and by the hitch of the towing tractor. Such a winged rotary mower is disclosed in U.S. Pat. No. 5,343,683 to Friesen.
Although single deck mowers of the trailing type are common, such smaller rotary mowers are often mounted on the three-point hitch of a tractor, such that the whole mower can be lifted off the ground by the tractor. When operating near the ground, the rear of these mounted mowers is supported by a castering wheel. Such a mounted mower is disclosed in U.S. Pat. No. 4,195,860 to Helams.
Rotary mowers are preferred for such applications as cutting the vegetation in the ditches along roads, since the vegetation is chopped up and dispersed, leaving a neat appearance. With conventional mowers following directly behind the tractor, the tractor travels on the slope of the ditch. Often these ditches slope sharply down from the road, making travel thereon unsafe.
Some small degree of offset can be provided for trailing rotary mowers by moving the tractor drawbar to one side, an adjustment commonly available on tractors. For mounted rotary mowers, an offset is provide in the Helams '860 hitch, and as well in the hitch of U.S. Pat. No. 6,138,445 to Toth. In all cases the degree of offset is too small to allow a tractor to remain on the road while cutting the ditch.
U.S. Pat. No. 5,957,475 to Pearen et al. provides an intermediate offset hitch apparatus that is hitched to the tractor on one side so as to tow behind the tractor. A rotary mower is hitched to the Pearen et al. apparatus at the rear of the opposite side. A pair of gearboxes and drive shafts connects the power take-off shaft of the tractor to the mower. The apparatus essentially provides a hitching location for the mower that is a clone of the tractor hitch itself, but offset sufficiently to allow the tractor to remain on the road while the mower cuts the slope of the ditch. The offset distance is not variable, and the apparatus must be removed in order to tow the mower directly behind the tractor.